Improvement in the manufacture of paper-pulp



UNITED STATES PATENT OFFICE.

CHARLES D. BROWN AND ELIAS B. DENISON, OF PORTLAND, MAINE.

IMPROVEMENT IN THE MANUFACTURE OF PAPER-PULP.

Specification forming part of Letters Patent No. 145,620, dated December 16, 1873; application filed December 9, 1873.

To all whom "it may concern:

Be it known that we, CHARLES D. BROWN and ELIAS B. DENIsoN, of Portland, in the county of Cumberland and State of Maine, have invented a new and useful Improvement in Wood Pulp; and we do hereby declare that the following is a full, clear, and exact description of the same.

Our invention is especially adapted to the production of aboard from wood pulp suitable .for the manufacture of paper boxes, resembling those usually made from straw-board; but the board produced from wood pulp, as hereinafter described, is far superior to strawboard, on account of the beauty and purity of its color.

A decided advantage results from its use in the manufacture of boxes over the use of straw-board, since boxes made from it require no paper lining, and because the board thus produced is thicker for weight than strawboard, and because the waste is much more valuable for paper-stock.

It is well known that wood pulp is manufactured in sheets to be used as paper-stock.

For this purpose many woods diifering from each other are used, and the pulps produced therefrom in sheets are as numerous and as various. No one of these sheets, however, is suitable to be used as box-board. No one of them combines the requisite consistency, strength, and external appearance. Poplar, bass, and white maple are the woods ordinarily reduced to pulp for the manufacture of paper; but sheets of pulp of these woods, or woods of a similar nature, although having a good color, are too soft and spongy for the manufacture of boxes. Pulp is also made from the resinous woods, such as spruce and fir; but sheets of such pulp, while they are harder and stronger, are of a dark color and warp badly.

By our invention, we produce a pulp that will make a board which has the requisite tenacity, and which at the same time lies flat, and has a smooth and even surface, and a good color. This we do by mixing pulp produced from poplar, bass, or similar woods with pulp produced from spruce, fir, or other resinous wood.

For box-board, we prefer tomix the two- Most wood pulp is now manufactured by grinding on stone, and when it is so produced it may be properly mixed by applying to the stone, in desired proportions, blocks of the different woods, in such manner that the ground products flow away together.

We claim- I. The process of making paper-stock by grinding together and combining resinous wood and white non-resinous wood, the resinous wood to yield the necessary sizing, and the white wood to give the stock tone or color, substantially as described.

2. Box-board made of pulp or stock from resinous woods combined with pulp or stock from white non-resinous woods, substantially as specified.

CHARLES D. BROWN. ELIAS B. DENISON. itnesses to signature of O. D. 13.:

PETER H. Fox, JNo. J. WHITE. \Vitnesses to signature of E. B. D.:

WM. M. SARGENT, WILLIAM S. TALNAN. 

